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Friday, September 26, 2014

Deconstructing ruckeri

Side view of Stanhopea ruckeri 'Tikal' ABG# 1997-0230
A Stanhopea flower is an exquisite thing, but trying to observe one from every angle while it's still on the inflorescence is a frustrating experience because of the compact arrangement of flowers. It's especially hard to get a direct look at the upper surface of the lip because the column blocks its view. The best way to look at Stanhopea flower is to remove it and take it apart.

Dorsal view of Stanhopea ruckeri 'Tikal' ABG# 1997-0230
Dorsal view of the column and lip without the two lateral petals and three sepals
Dorsal view of the lip without the column
Ventral view of the lip
Ventral view of the column
Dissecting these flowers increases my admiration for them. And the powerful fragrance that is released inside our small closed library is wonderful. Some of them (like Stanhopea embreei, 99% trans-methylcinnamate) I want to inhale over and over again. How exactly do the Euglossine bees experience this fragrance, I wonder?

Tuesday, September 23, 2014

Two Stanhopea ruckeri Clones

Stanhopea ruckeri flowers in August and September in our greenhouses. It has been fascinating to observe the different color forms and scent variations among our plants. S. ruckeri varies in color from albino to apricot, and may occur with or without eyespots and scattered dots. Some clones have a scent that is almost undetectable. Others have a light floral fragrance. Still others smell like candy Red Hots. The morphology of their flowers is pretty similar. The biggest obvious difference is their scent chemistry.

The first two pictures show ABG# 1990-1503, a clone with lots of spots on the petals and sepals and two barely visible eyespots on the dorsal side of the hypochile. It has a light rosy floral fragrance whose main component is phenyl-ethylalcohol.

On the underside of # 1990-1503's lip are two more faint eyespots.

Another plant, # 1997-0230, has two bold eyespots. This clone smells like cinnamon (it's a mixture of trans-cinnamaldehyde, cinnamyl-alcohol and cinnamyl-acetate) and benzylaldehyde.

This plant also has a second pair of pale eyespots on the underside of the lip.

The extra sprinkling of tiny spots on the underside of the column were a surprise. The spots and the fragrances remind me that pollinators experience a sensory world very different from ours.

Stanhopea ruckeri, with its different chemotypes, is a puzzling entity. Calaway Dodson suggested that S. ruckeri may be a group of natural hybrids between S. wardii and S. oculata, but more research is needed.

We grow our plants in a mixture of long-fibered premium sphagnum and coarse chopped tree fern fiber. Stanhopea ruckeri is easy to grow in an intermediate (58º night minimum) temperature greenhouse and 60% shade. It grows quickly, produces multiple spikes and makes a handsome overwhelmingly fragrant specimen basket.

Friday, September 19, 2014

Stanhopea Season 2014

Stanhopea oculata ABG# 96-0801 flower, lateral view
Lots of activity buzzing around our Stanhopea collection this summer. Last year's newly divided plants are now big enough to carry capsules, so I've been busy pollinating our plants. In addition, photographic documentation of our collection is now possible with a newly developed image library that references our plant records database. (Thanks Michael Wenzel and Cindy Jeness: you guys are terrific!) So I have also started systematically photographing each Stanhopea accession.

Stanhopea oculata ABG# 96-0801 flower
For each accession, there will be six images that show morphological features that are diagnostic for Stanhopea. When an identification needs verifying, like this one, I send the images to Dr. Mark Whitten and Dr. Günter Gerlach.

Stanhopea oculata ABG# 96-0801 lip and column
As I learned from them, it's not always easy to put a name on a Stanhopea. The plant pictured here, which we received as Stanhopea oculata, is a good example. It has features in common with S. oculata, S. whittenii and S. dodsoniana. Which is it? S. oculata  varies enormously in the size and morphology of its flowers over its wide range (Mexico to Venezuela). Its fragrance is similar to several other morphologically similar species with whom it shares pollinators, making the existence of natural hybrids within populations likely. In fact, Rudolf Jenny states that S. oculata populations frequently consist of a mixture of both of the parents, natural hybrids, and back-crosses. So, is Stanhopea oculata five new species with some shared characteristics? Or do we treat it as one widespread species complex on its way to becoming new distinct species? What is Stanhopea oculata? And what the heck do I write on this plant's label?

Stanhopea oculata ABG# 96-0801 lip without column, dorsal view
Right now, there's not a good answer to these questions other than 'more work needs to be done.' For now our plant's identity remains as we received it: Stanhopea oculata ABG# 96-0801.
Stanhopea oculata ABG# 96-0801 lip, ventral view
In spite of the taxonomic uncertainty, I'm having a blast. Typically, I use the oldest flower on the inflorescence as the capsule parent and the youngest flower for dissection. Dissecting them inspires awe and admiration. These plants are so beautiful. It's a privilege to do be able to document them.
Stanhopea oculata ABG# 96-0801 column, ventral view

Friday, September 12, 2014

Paphiopedilum dayanum

That fringe of long silky hairs. Paphiopedilum dayanum always gets a second look from me. True, there are other Paphs with hairs, but this is the only one in our collection that triggers a grooming impulse. What other orchid has petals that need combing?

Paphiopedilum dayanum is one of those select plants that grows on Borneo's Mt. Kinabalu and nowhere else. Like many terrestrial orchids it occupies a specialized micro-habitat. Phillip Cribb reports that it grows in leaf litter under bamboo and at the base of trees on steep ridges around the mountain at 300 to 1450 meters elevation.

Why the the hairs on the petals? They may be an adaptation to attract flies that can pollinate the flowers. Hairs, warts, aphid-like bumps. Carrion colored flowers. Together, these comprise a syndrome associated with fly pollination.

Paphiopedilum dayanum has been trouble-free for us. It seems fine with temperatures on the warm side of intermediate (60 to 62º night minimum) in a shady greenhouse in a mixture of fine fir bark, chopped moss, charcoal and perlite.


Thursday, September 11, 2014

Lycaste schilleriana var. rosea

Among all of our Lycaste species, this could be my favorite. Of the two or three dozen Lycaste species in cultivation, most fall within the traditional spring floral color spectrum--pinks, yellows, whites. Not this one.

This is Lycaste schilleriana var. rosea. I love the deep olive green of the sepals. They are olive on the exterior and bronze on the inside.

Even more remarkable is the extraordinary length of its sepals. Each sepal is about 3 inches long, giving L. schilleriana the widest flowers in the genus.

The buds look like elongated beaks.

Lycaste schilleriana var. rosea likes a greenhouse at the cool end of the intermediate temperature spectrum. For now, our plant resides in our shadiest most humid greenhouse right next to the wet wall, where the summer daytime temperature maxes out at about 83º. If the current warming trend continues, we may have to move it to the Tropical High Elevation House.

Lycastes are pollinated by Euglossine bees. Lycaste schilleriana is known from Panama and Colombia where it grows as a lithophyte at around 1400 meters elevation.

Thursday, September 4, 2014

Identifying our Acineta

Great news: we have a name on our mystery Acineta. And it's not erythroxantha, the name that was on the label when we received it from a Panamanian grower. In order to make the determination, it was necessary to dissect a couple of flowers and send photographs to Dr. Günter Gerlach at Münich Botanical Garden. He was very specific about which floral parts he needed to see. Here is what I sent him.

Shown above, I've removed two lateral sepals and one of the lateral petals in order to show the lip in side view. Each side of the lip has two deep incisions, creating a side lobe. The column is white and partly hidden by the lip.

Next, I made a longitudinal cut through the lip to show it in cross section. The interior has blood red spots. You can see the callus, chair-shaped and white in cross section.

Then, I removed a second flower and cut off everything but the the lip and the ovary. Above, you can see the lip, face up. It is shaped like a shallow scoop. Just above the broadly U-shaped edge of the lip is the callus, which is wide and thin seen from above. The lip and callus are important diagnostic features.

The underside of the lip.

The pollinarium, including two pollinia and a sticky orange viscidium.

This must have been an easy call for Dr. Gerlach, who described this species, Acineta mireyae, in 2003. Additonal photos appear on his amazing Stanhopeinae image data base, where you can compare A. mireyae with some closely related Central American species, Acineta sulcata and Acineta sella-tucica. In fairness to the grower from whom we purchased our plant, I should mention that it was shipped to us in 2002, before publication of the epithet mireyae. Our thanks to Dr. Gerlach for solving this mystery!

Tuesday, September 2, 2014

Open at last... But what is it?

It's not very often that we flower an Acineta, so there has been tremendous anticipation as the spike of this Acineta erythroxantha has elongated to an astonishing 28 inches. Bud development has been agonizing. ('Slow as Christmas' is the phrase around here.) But at last we have open flowers. And a surprise...

This isn't actually Acineta erythroxantha at all, as the label would indicate. The lip is very different. We received this plant in 2002 as A. erythroxantha from a Panamanian source. Could this be the Panamanian species, Acineta mireyae?

For an answer, I'm turning to Dr. Mark Whitten at University of Florida-Gainesville and Dr. Günther Gerlach at Münich Botanical Garden, rockstars of Euglossine bee-orchid research. Acineta identification is tricky and I want a definitive answer. Dr. Gerlach is the author of the original 2003 publication of  A. mireyae, so I'm sending pictures of these flowers, dissected. We'll see what he says.

Acineta belongs to the Stanhopeinae subtribe, and like Stanhopea, they are pollinated by Euglossine bees of the genus Euplusia.

The waxy fragrant flowers are carried on a pendant raceme. The sepals and petals form a hood around the column, creating a tunnel for the bee to enter. The bee obtains the fragrance by scratching at the base of the lip inside the tunnel. As the bee backs out, the viscidium of the pollinarium is stuck to the bee's scutellum. If the bee enters another Acineta flower, the pollinia are placed on the stigma as the bee backs out, and thus the flower is pollinated.


Wednesday, August 27, 2014

Saving Monkeyface and its Habitat

Monkeyface Orchid (Platanthera integrilabia) is one of our prettiest native orchids, though if you've seen it you can consider yourself lucky. Although it ranges from the southeastern to the south central United States, Monkeyface Orchid is rare throughout its range, occupying a very limited wetland niche: seepage bogs or slopes, and streamheads in open forests. There are only eight known populations in the Georgia Piedmont, all of them decreasing in size and vigor. Urban encroachment, large scale conversion of habitat into timber production and competition from invasive exotic or overstory plants have made Platanthera integrilabia a threatened species in Georgia and a candidate for protection under the Endangered Species Act.

The good news is that some constructive action is underway to protect Monkeyface Orchid in Georgia. Four sites in Georgia are the focus of a new conservation project funded by the National Fish and Wildlife Foundation's Five Star/Urban Waters Grant Program. It will be conducted by ABG in partnership with a number of other organizations.* The goal of the project is to restore the habitat and reintroduce plants grown from seed (collected on site and germinated in ABG's lab) into their restored habitat.

Restoration will take time and lots of hard work. Matt Richards, ABG's Conservation Coordinator, is spearheading the project for ABG. According to Matt, these sites are under constant pressure from illegal trash dumping, competition from invasive exotic plants, closure of the forest canopy and herbivory. The first step will be to map and survey each site. Next, a management plan will be developed for each site, taking into account the threats specific to each site, with the immediate goal of protecting the existing plants. Some sites may need deer fencing. At others, saplings will be removed and mature trees girdled to remove competition and open the canopy. Invasive exotic plants will be removed; garbage will be hauled away.

Monkeyface Orchid flowers in August. Capsules mature in about three months. Matt will collect capsules and germinate the seed in ABG's lab. The germination rate in cultivation, according to Matt, is low compared with that of tropical orchids, only about 50%. In the fall, Matt will plant deflasked seedlings in beds in our nursery, where they will remain for about a year.

Once the habitat has been restored and a management plan enacted, Matt and his associates will reintroduce seed propagated plants. At this stage the goal will be to establish flowering sized plants that produce seed. Fall is the season that Matt prefers for outplanting of year-old seedlings. It takes another two years for the plants to flower. Habitat management will continue in the meantime, and the sites will be monitored.

In the United States many threatened ecosystems occur in and around urban areas, and they are a high priority for restoration despite their often degraded condition and remnant status. "It's significant that we have wetlands and natural areas in Metro Atlanta that harbor rare plants like Monkeyface Orchid," said Dr. Jenny Cruse-Sanders, Vice President for Science and Conservation at ABG. It is important that we focus our efforts and expertise towards conserving this species in our own community."

Congratulations to our conservation team on this exciting new project!

*NFWF Five Star/Urban Waters Restoration Partners:
Atlanta Botanical Garden
Georgia DNR Non-Game Conservation Section
Georgia State Parks
Big Canoe POA
Sewanee Mountain Preserve
The Dunn Family
Rock Spring Farms
Georgia Environmental Restoration Professionals
Georgia DOT
Georgia Power
Chattahoochee Nature Center
Lovett School
Grady High School
Peachtree Garden Club
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